Announcement data is sent using IP multicast and the User Datagram Protocol (UDP).
Under SAP, senders periodically transmit SDP descriptions to a well-known multicast address and port number (9875).
Two authentication schemes are supported: The message body may optionally be compressed using the zlib format as defined in RFC 1950.
VLC media player monitors SAP announcements and presents the user a list of available streams.
[3] SAP is one of the optional discovery and connection management techniques described in the AES67 audio-over-Ethernet interoperability standard.